Method of making fans



Feb. 20, 1951 H. c. HUEGLIN METHOD OF MAKING FANS Filed July 25, 1947 2 Sheets-Sheet l INVENTOR. Z fie/wzarz Hu egZz 'w BY I M, lazza 10% A7715 am w Feb. 20, 1951 H. c. HUEGLIN METHOD OF MAKING FANS 2 Sheets-Sheet 2 Filed July 25, 1947 Patented Feb. 20, 1951 METHOD or MAKING FANS Herman C. Hueglin, Chicago, Ill.. assignor to Ail-mas er Corporation, Chicago, 111., a corpora.-v

tion of Illinois Application July 25, 1947, Serial No. 763,715

This invention relates, in general, to fluid circulating devices, and has particularrelation to an improved fan.

More particularly, the fan and method of assembling of the present invention may be characterized as an improvement upon the invention disclosed and claimed in my copending application Serial No. 709,833, filed November 14, 1946. While the present fan is adapted for operation on air, for example, as an air circulator or the like, it is to be understood that the present invention may be used in fans or impellers for operation on other fluids, or for use elsewhere as suitable and desired.

As stated in my above identified copending application, prior devices of the character described have been confronted with an expen ive labor cost to obtain proper balance, and particularly dynamic balance of the fan. Any slight cit-balance produces an eccentric motion of the fan in operation, and this results in objectionable vibration and wear, and in different pressures of the air or other fluid against the blades and resulting back pressures and lowering of efficiency.

Whether complete fans are cast in one piece, or whether the blades and hub of the fan are made up in separate parts, it has been extreme- 1y difiicult, if not practically impossible, to obtain symmetrical distribution of the weight in all concentric lines from the axis of the fan to the tips of the blades. And it has been extremely difiicult, if not practically impossible, to attach the blades to the hub of the fan uniformly and without producing asymmetry or off-balance in the fan.

Where the blades and hub are fabricated or cast in one piece, it has been extremely diffioult, if not practically impossible, to obtain the desired balance. In finishing the blades and hub of the fan, or cleaning the pattern or mold, a variation, as slight as .001 of an inch, would change the results tremendously. If the bore in the hub for receiving, for example, the motor shaft is not accurately positioned and exactly at the center of mass of the blades at all points throughout the length of the bore, unbalance and the disadvantages which accompany the same result. Even with careful and expensive machine work, if balance is obtained, it has been more or less accidental than the rule.

Where weight is removed from or applied to the fan in an effort to bring it into dynamic balance, there is no way to determine just where the weight should be applied or removed to bring the fan into static and dynamic balance, i. e., with 2 Claims. (01. 29-1563) symmetrical distribution of the weight in all concentric lines from the axis of the fan to the tips of the blades. Consequently, even though weight is added .or removed in an effort to bring the fan into static balance, the fan may still not be in dynamic balance.

In such case, one blade may apply more pressure than another and back pressures may result.

Moreover, in casting blades in one piece, difficulty is involved in the mold. It is practically impossible to make the mold cavities identically the same for each blade constituting the fan. It is also practically impossible to bore a hole for mounting the prop ller or fan on a drive shaft sufficiently accurately to obtain the desired objectives. In addition, casting blades in one piece requires an exceedingly large mold flask and large amount of sand or other mold material.

One of the main objects of t e present invention is to provide an improved fan and method of assembling with which the problems previously encountered are overcome.

Another object of the invention is to provide an improved fan and method of assembling in which symmetrical distribution of the weight in all concentric lines from the axis of the fan to the tips of the blades, whereby to provide accurate static and dynamic balance, is automatically obtained without expensive labor operations.

Another object of the invention is to provide for balancing in the manner described a fan or propeller comprising a hub and a plurality of separate blades adapted to be joined together at the hub of the fan.

Another object of the invention is to provide a fan comprising, in combination, a central member, a plurality of identical molded blades with integral hub portions assembled circumferentially about the central member, and improved means joining the hubs of the blades together with the blades extending generally radially from the central member.

Another object of the invention is to provide a method of making the fan which comprises molding a plurality of identical blades each with an integral hub portion, assembling the blades with the integral hub portions disposed circumferentially about a central member and with the blades extending generally radially from said member, and joining the blades of the fan together.

Another object of the invention is to provide a fan comprising, in combination, a central member of tubular form. a plurality of identical molded blades with integral hub portions having tapered end surfaces and of arcuate form adapted to surround and, if desired, to fit against the outer periphery of the central member of tubular form, and end caps having tapered surfaces for cooperation with the tapered surfaces of the blade hubs and between which the hubs of the blades are adapted to be secured.

Another object of the invention is to utilize the central member of tubular form for centering the blades and to provide improved means for clamping the end caps together with the hubs of the blades therebetween during completion of the fan; also means for clamping the end caps together, with the hubs of the blades therebetween, after complet on of the fan.

Another object of the invention is materially to reduce the size of the molding flask and the amount of mold material required to produce the fan.

Another object of the invention is to provide a fan having Various features of novelty and advantages, and which is particularly characterized by its s mplicity in construction, its economy in manufacture, its static and dynamic balance, and its effectiveness in use for the intended purposes.

Further objects and advantages of the invention will appear from the following detailed description, taken in connection with the accomp-anying drawings which illustrate the manner of constructing and assembling an illustrative embodiment of the present invention.

In the drawings:

Figure 1 is a front elevational view of a fan embodying the present invention;

Figure 2 is a side elevational view of the fan shown in Figure 1;

Figure 3 is a fragmentary front elevational view of the hub of the fan, with the adjacent end cap partially broken away;

Figure 4 is a fragmentary detail section taken on the line 4-4 of Figure 3;

Figure 5 is a fragmentary perspective view of the inner end of one of the blades;

Figure 6 is a diagrammatic sectional view of a mold showing the step of casting or molding the identical blades with the hub portions integral with the inner ends thereof;

Figure '7 is a sectional view taken on the line 7-4 of Figure 6; and

Figure 3 shows the method of assembling and joining the blades and end caps of the fan together.

Referring now to the drawings, the fan selected for illustration comprises a central tubularmember or sleeve I, a plurality of blades 2, end caps 3 and 4, and means-for example, bolts 5 or the like-for securing the parts rigidly together.

The blades 2 may be made of cast magnesium, cast aluminum, molded plastic material or any other suitable or preferred material, and all of the blades are preferably cast or molded to identical form in one and the same mold cavity 6 (Figures 6 and 7) to produce uniform or symmetrical distribution of-the weight in all concentric lines from the inner ends of the blades to the tips of the blades. The mold parts 1 and 8, shown in Figures 6 and 7, may be positioned, for example, by positioning pins 9.

Each blade 2 has, at its inner end, an integral arcuate hub portion 10 adapted to surround the central tubular member l when the blades 2 are applied thereto, as will presently appear. The inner arcuate surfaces of the hub portions preferably fit around the outer periphery of the tubular member I, and the radial surfaces l I of the hub portions l0 preferabl abut when'the blades are applied to the tubular member I.

Each of the opposite ends of each hub portion has an external tapered end surface E2 of arcuate form cast or molded as a unitary part thereof. When the parts are assembled, these tapered surfaces form external tapered surfaces of substantially complete annular form at the ends of the hub of the blades, which tapered surfaces l2 enter the marginal flanges l3 of the end caps 3 and 4; and seat against corresponding internal tapered surfaces M of annular form in the respective end caps.

For the purpose-of joining the blades together, holes l5 may be drilled through the hub portions [0 and end caps 3 and 4 after assembling the parts and while they are clamped together, as will'presently appear. Bolts .5 are then inserted through holes [5, and nuts I? are screwed onto the ends of the bolts to clamp the parts rigidly together, as shown in detail in Figure 4. The end cap 3 is rigidly joined to tubular member or sleevel, for example, by having tight pressed fit thereon. The other end cap 4 may also have tight pressed fit on the other end of sleeve l, although that is not so essential and therefore may vary within the scope of the present invention.

As shown in Figures 6 and 7, the mold parts may, if desired, have a pin-like insert l8 of cylindrical form for producing the inner arcuate surfaces in the hub portions ill of the blades of the desired precision. This is merely illustrative, and may vary as suitable or desired within the scope of the present invention.

The tapered surfaces l4 may be machined with precision in the end caps 3 and 4, but I also contemplate casting or molding all of the end caps with the tapered surfaces Hi precision cast or molded therein in one and the same mold cavity to assure that all of the end caps and the tapered surfaces thereon will be identical and of a character for the desired cooperation with the tapered surfaces IZ of the blades 2. Each end cap 3 and 4 has an opening 20 accurately located at the axis thereof.

In assembling the fan, the end cap 3 is placed, for example, on a surface plate 2|, with a stud 22, which projects accurately at right angles to the surface of plate 2|, extending through the opening 20 in end cap 3. The stud 2?. may be rigidly secured to surface plate 2|, for example, by screwing it therein as shown at 23.

The central tubular member is then placed telescopically over stud 22, and its adjacent end is driven into the opening 20 into tight or rigid pressed fit engagement with the end cap 3. The hub portions Id of blades 2 are then assembled about sleeve l, with their tapered surfaces 32 seating against the tapered surface I 4 of cap 3 as shown in Figure 8. A suitable jig (not shown) on surface plate 2! preferably holds or locates,

plied by air cylinders or the like. or otherwise as desired. For purposes of illustration, I have shown a sleeve 25 screwed onto the upper threaded end of stud 22, at 26, and provided with a pin or handle 27 for turning the same to apply the desired pressure.

By grasping the pin or handle 21 and turning the sleeve 25, its cooperation with the adjacent end cap 4 clamps the parts firmly between sleeve 25 and surface plate 21 as shown in Figure 8. The sleeve 25 may be recessed or relieved at 23 to avoid engagement with the adjacent end of sleeve i in the clamping operation, as described.

Then with the parts of the fan tightly clamped together. the holes I5 are drilled by a drill 30, with their axes in precise parallelism with the axis of the sleeve I. The holes extend through the hub portions l I] and end caps 3 and 4. With the end cap 4 having pressed fit on the adjacent end of sleeve I the clamping means may then be removed, whereupon bolts 5 may be inserted through holes l5 and nuts I! screwed onto the ends of the bolt to secure the parts of the fan firmly together.

While the heads of bolts 5 and nuts I! are shown projecting from the end caps 3 and 4, it is to be understood that they may be countersunk into the end caps if their projection therefrom is not desired. It is also to be understood that I contemplate within the scope of certain aspects of the invention screwing the outer ends of bolts 5 directly into tapped openings in end cap 4, although this is not as desirable as the illustrated embodiment of the invention.

In use, the motor shaft or the like is inserted into the opening through sleeve l which forms a permanent part of the fan, and the fan may be secured to the motor shaft in any suitable manner (not shown), for example, by set screws or by keying it to the shaft or the like.

The present invention enables production of relatively large diameter fans or propellers in relatively small casting flasks, thus simplifying and producing economy in the making of the fan. For example, a 48-inch diameter propeller cast in one piece requires a molding flask about 54" X 54", whereas the present invention requires only a flask about 28" x 16", and, for other designs of blade shapes, as small as 28 x 6" or less, depending on the width of the blade.

Aside from the improvements in function set forth and other improvements which are inherent in the device, the elimination of a spider, rivets and the like provides an improved appearance.

The embodiment of the invention shown in the drawings, is for illustrative purposes only, and it is to be expressly understood that such drawings and the accompanying specification are not to be construed as a definition of the limits or scope of the invention, reference being had to the appended claims for that purpose.

I claim:

1. The method of making a fan and providing accurat static and dynamic balance therein, which comprises screwing the threaded inner end of a stud into a surface plate to position extending outwardly from said surface plate and with its axis at right angles to the outer surface of the surface plate, applying from the outer side and against said surface plate a first end cap having a continuous internal tapered surface and an axial opening of greater internal diameter than said stud and through which'said-s tud extends, applying a central tubular member telescopically over said stud from its outer end and drivingthe inner end of said tubular member into the opening in said first end cap to provide rigid pressed fit engagement between said first end cap and the adjacent end of said tubular member, forming a plurality of identical blades with integral arcuate hub portions having first externally tapered surfaces at one end matching the internal taper of said. first end cap, assembling the blades with the hub portions disposed circumferentially about said central tubular member and said first externally tapered surfaces seating against the internal tapered surface of said end cap, the hub portions of said blades having second externally tapered surfaces at their outer ends, applying over the outer end of said central tubular member and into rigid pressed fit with the outer end of said tubular member a second end cap having an internal tapered surface matching the second externally tapered surfaces at the outer ends of the arcuate hub portions of said blades and which are driven into seating engagement therewith by the application of said second end cap, forming, while the hub portions of the blades are clamped between the end caps, holes through said end caps and hub portions parallel with the axis of the tubular member, and inserting bolts through said holes to secure the parts together.

2. The method of making a fan and providing accurate static and dynamic balance therein, which comprises screwing the threaded inner end of a stud into a surface plate to position extending outwardly from said surface plate and with its axis at right angles to the outer surface of the surface plate, applying from the outer side and against said surface plate a first end cap having a continuous internal tapered surface and an axial opening of greater internal diameter than said stud and through which said stud extends, applying a central tubular member telescopically over said stud from its outer end and driving the inner end of said tubular member into the opening in said first end cap to provide rigid pressed fit engagement between said first end cap and the adjacent end of said tubular member, forming a plurality of identical blades with integral arcuate hub portions having first externally tapered surfaces at one end matching the internal taper of said first end cap, assembling the blades with the hub portions disposed circumferentially about said central tubular member and said first externally tapered surfaces seating against the internal tapered surface of said end cap, the hub portions of said blades having second externally tapered surfaces at their outer ends, applying over the outer end of said central tubular member and into rigid pressed fit with the outer end of said tubular member a second end cap having an internal tapered surface matching the second externally tapered surfaces at the outer ends of the arcuate hub portions of said blades and which are driven into seating engagement therewith by the application of said second end cap, forming, while the hub portions of the blades are clamped between the end caps, channels through the hub portions and opening through the end caps parallel with the axis of the tubular member, and inserting clamping members through said channels to secure the parts together.

HERMAN C. HUEGLIN.

(References on following page) 7 REEEBENGESI 01mm UNITED STATES PATENTS Number Name Date Sharps Nov- 22, 1870 McCay Jan; 30, 1872 Simmons 1 Feb. 9, 1886 Humphrey etal. June 11,1907 Shaw Nov. 5, 1907 Loetzer Dec. 5, 1911 Number 8 Name. Date Henrichsen ..V Dec. 29,1914 Tedman Nov. 5,.1929 Forsyth. Apr. 30, 1935 Barret June 22,, 193.8 Schubert Dec. 7, 1,943 Bohaboy Oct. 14,1947

FOREIGN PATENTS Country Date Great Britain Aug. 3, 1916 Germany Feb. 8, 1933 

